1. Field of the Invention
The present invention relates generally to telescope mounts, and more particularly, to a disc-based alt-azimuth mount for telescopes.
2. Description of the Prior Art
A wide variety of telescope mounts are available for both astronomical and non-astronomical telescopes. These generally fall under two broad categories, namely equatorial and altitude-azimuth mounts. Equatorial mounts are designed to follow the celestial sphere by moving the telescope in one axis only. An alt-azimuth mount, on the other hand, is designed to move in two axes to follow both the celestial sphere and the vertical altitude dimension.
Because of its simplicity, the alt-azimuth mount has gained popularity in recent years as a multi-purpose astronomical and non-astronomical mount. The new professional telescopes are now being built with alt-azimuth mounts and computer driven motors moving in both axes to track celestial objects. The mount has also gained popularity with the advent of new precision-built and optically-correct wide field refractor (lens in front) telescopes being used for astronomical and terrestrial objects.
Unfortunately, existing alt-azimuth telescope mounts have proven to be quite amendable to vibrations and do not remain rigid to outside forces such as wind or touch. Such vibrations are most evident in single arm mounts and intensify as the length of the arms is increased. Although adding a second arm has reduced this problem somewhat, it has lead to a host of other design deficiencies, such as not being able to carry telescopes of varying widths. One notable drawback found in existing alt-azimuth telescope mounts is that they are not able to handle telescopes of varying sizes without the addition of counter-balance devices and do not permit the mount to swing freely without interference from the telescope hitting the base of the mount.
A further problem encountered with existing alt-azimuth telescope mounts is that they are not able to handle various size loads such as cameras, eyepieces and the like without unwanted movement caused by imbalance. Many telescopes allow the observer to interchange eyepieces, allowing an increase or decrease in magnification. Cameras may also be used in place of eyepieces in order to take pictures. Modern eyepieces weight can range from as little as two ounces for high magnification, to over two and a half pounds for a wide field low magnification. If the telescope is balanced for a heavy eyepiece and the eyepiece is removed, the telescope will rotate forward. Likewise, if the telescope is balanced for a light weight (or no eyepiece), then the telescope will drop in the rear. To overcome this problem, some mounts have locks to prevent the axis from moving. The observer moves the telescope to the object and locks the axis. However, the object seldom remains stationary (a sighted dear runs or the earth rotates, for example). In order to address this problem, designers have added slow motion mechanisms. These mechanisms, however, have generally proven cumbersome and inadequate in practice because the mount axis must be locked during use. Similarly, friction locks have not adequately addressed this issue.
Additionally, existing mounts often do not maintain all axes and planes perfectly orthogonal with each other as required for accuracy when electronic shaft encoders are utilized with computerized locaters, commonly known in the art as setting circles. Significant errors are introduced where the axes of the telescope mount are not perfectly orthogonal.
Accordingly, there is an established need for a disc based alt-azimuth telescope mount for use with any of a variety of existing telescopes that addresses and overcomes the aforementioned problems and disadvantages found in existing telescope mounting systems.